1. Field of the Invention
The invention relates to vacuum cleaners and in particular to vacuum cleaners having cyclonic dirt separation. In one of its aspects, the invention relates to a cyclone separator with an improved exhaust grill.
2. Description of the Related Art
Vacuum cleaners employing cyclone separators are well known. Some cyclone separators follow textbook examples using frusto-conical shape separators and others use high-speed rotational motion of the air/dirt to separate the dirt by centrifugal force. Typically, the cyclonic separation chamber is positioned above the dirt collection chamber in a vertically stacked orientation. Working air enters and exits at an upper portion of the cyclone separator and debris is collected in lower portion. Alternatively, the cyclone separator and dirt collection chamber can be oriented horizontally within the cyclone module. This orientation can reduce the overall height of the cyclone module, which is particularly desirable for canister vacuum cleaners to lower the center of gravity and improve stability of the unit as it rolls along the floor.
BISSELL Homecare, Inc. has developed a dual function canister vacuum cleaner that can accommodate a standard vacuum filter bag or an interchangeable bagless cyclone module. The cyclone module is configured so the cyclone separation chamber is positioned adjacent to the dirt receptacle along a horizontal plane. The air flowing through the cyclone separator passes through an exhaust grill before exiting the cyclone module through a filter assembly on the bottom of the module. The exhaust grill is configured to be easily removable by a user for cleaning.
U.S. Pat. No. 7,381,236 to Lee discloses a cyclone module with a cyclone separation chamber and a cyclone dust collection chamber arranged in parallel where the dust collector has a backflow prevention member disposed at one sidewall of the dust chamber to prevent collected dust from flowing back into the cyclone chamber.
U.S. Patent Application Publication No. 2006/0130441 to Oh discloses an exhaust grill for a cyclone separator wherein the air passages in the grill have a leading surface facing toward the direction of air flow around the grill. It is said that the direct flow of air into the grill prevents stagnant vortices from forming in the grill air passages, thus preventing debris build-up.
U.S. Pat. No. 7,445,655 to Bock discloses a canister vacuum cleaner that can accommodate a filter bag or a dust collection container having a clip to hold a bag closure plate. A pivoting carrier in the dust compartment includes locking members which overlap an edge of the dust compartment so that the vacuum cleaner lid cannot be closed when either the filter bag or dust collector is absent.